1. Technical Field
The method and apparatus of the present invention relate generally to wheelchair seats. More specifically, they relate to an apparatus and method wherein the height of a wheelchair seat is continuously adjustable throughout its operating range. The improved, adjustable wheelchair seat is adapted to be used on wheelchairs having a conventional construction and does not require any substantial modification of an existing wheelchair but instead requires only the removal of the conventional seat. The seat requires no tools for adjusting its height.
Currently, most wheelchair seats if they can be adjusted at all, are adjustable only in specific discrete steps. Thus, depending on the gradations of adjustment positions, the user may not be able to find the proper height.
Additionally, some of these seats are unable to be adjusted for different front and rear heights. Such an uneven adjustment might be desirable in the case of a person having a tendency to lean forward in the seat with the possibility of falling out of the chair. Consequently, it is sometimes good to have a seat which could be adjusted for a greater height in the front than in the rear thus urging the person backwards and against the seat back, tending to keep them in the chair.
Additionally, a great number of wheelchair patients like to utilize their feet as a source of locomotion by moving their feet on the ground while seated in the chair. The legs and feet have a tendency to remain stronger than the arms and thus can provide for better mobility than use of the arms in conjunction with the drive wheels. Additionally, this provides a source of exercise for the patient. Thus it is important to provide a seat which is adjustable in height so as to permit the patient to place his or her feet on the floor.
2. Description of the Prior Art
As mentioned above, the majority of wheelchairs are not adjustable in height. Rather, the leg rests of the chair are adjusted in height in order to accommodate people of different heights. However, there are some prior art examples of wheelchair seats which may be adjusted in height.
One example of such a prior art height adjustable seat is the "Jay Adjustable Solid Seat". This adjustable seat provides an example of a seat which although adjustable in height, may only be adjustable in discrete positions. Adjustment is made by means of a plurality of hooked bars attached to the horizontal mounting bars of the chair. The hooked bars comprise a discrete number of adjustment locking positions. Therefore, height adjustment is limited to these discrete locking positions, i.e. no "in between" positions. Additionally, a tool is required to make the adjustment between positions.
Another prior art example of a height adjustable wheelchair seat is Griffin, U.S. Pat. No. 3,076,678, which discloses a fabric, hammock-type seat suspended between vertically slidable rods mounted on the wheelchair side posts. The rods are raised and lowered by means of straps which are extended over rollers in the wheelchair arm rests. The straps are trained around an idler roller and drive roller for raising and lowering the seat in response to rotation of the drive roller. Thus, special arm rests and corner posts are required in order to accommodate the idler and drive rollers.
Therefore, it is a primary objective of the present invention to provide a height adjustable wheelchair seat which is adapted for use on conventional wheelchairs without the requirement for special fittings.
Another objective is to provide a seat which requires no tools for adjustment of its height.
Another objective of the present invention is to provide a height adjustable wheelchair seat which may be mounted to a conventional wheelchair without extensive modification thereof.
Another objective of the invention is to provide a height adjustable wheelchair seat which may be adjusted in height continuously throughout the height adjustment range without being limited to discrete positions.
Another objective is to provide a height adjustable seat which may be adjusted to different heights in the front and rear sections thereof.
Another objective is to provide a seat which is constructed of durable material impervious to liquids and the like.
Another objective is to provide a seat comprising a securement means for securing the seat in position once the height adjustment has been made.
Another objective is to provide a seat of a design which may be utilized on wheelchairs having some frame deformities due to extended use.
A final objective is to provide a seat which may be adjustable in height so as to permit a patient to place his or her feet on the floor in order to provide a means of locomotion.